code: def _update_out_channels(self, channel, feature_idx, feature_maps):
      if feature_idx in feature_maps:
          self._out_channels.append(channel)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import paddle.nn
  import paddle.nn.functional
  from paddle import ParamAttr
  from paddle.regularizer import L2Decay
  from paddle.nn.initializer import KaimingNormal
  from ppdet.core.workspace import register, serializable
  from numbers import Integral
  from ..shape_spec import ShapeSpec
label_desc: Use image node_id 2 for calling the MobileNet obj's underlying member method code with example usage: obj._update_out_channels(channel, feature_idx, feature_maps) without return types